Add a DEPS variable that points to src/ for angle

4c984bc7664755d701c75b49b795678e164551e3 requires angle to call a script
in build/util/, but this directory is in src/ in chromium, and ./ in
angle.  Similar to how angle_root was defined to point to the right
directory in each project, src_root is added to point to src/ or ./
depending on the project as well.

This is necessary for angle to be able to roll its dependencies forward.

Bug: angleproject:2892
Change-Id: I691d378c76bb238071a59db2298206eba55278bb
Reviewed-on: https://chromium-review.googlesource.com/c/1283830
Reviewed-by: Geoff Lang <[email protected]>
Commit-Queue: Shahbaz Youssefi <[email protected]>
Cr-Commit-Position: refs/heads/master@{#600125}
diff --git a/DEPS b/DEPS
index ff3889a..151c198 100644
--- a/DEPS
+++ b/DEPS
@@ -87,8 +87,11 @@
   # as an expression.
   'cros_download_vm': '"{cros_board}" == "amd64-generic"',
 
-  # ANGLE's deps are relative to the angle_root variable.
+  # ANGLE's deps are relative to the angle_root variable, except for what's
+  # shared with chromium, such as build/, testing/, etc which are relative to
+  # src_root.
   'angle_root': 'src/third_party/angle',
+  'src_root': 'src',
 
   'android_git': 'https://android.googlesource.com',
   'aomedia_git': 'https://aomedia.googlesource.com',